1. Field of the invention
This invention relates to an improved method of forming a building panel, and particularly in forming the building panel including the door and access opening and, in one aspcct, to a completed door panel unit including the wall members, the door frame, door, closure, and lock unit.
2. Description of the Art
The present invention relates to an improvement in the method of forming a building panel or wall unit for a portable building and to provide the wall unit and door with sufficient rigidity to form a serviceable longer-lifed unit. While vacuum molding has been utilized for the forming of large molded plastic or polymeric parts and that twin sheet forming of parts is known in the industry, the formation of a large twin sheet part to form a wall unit for a portable building structure and to form the unit having the access opening such that the part may be cut to form the opening and assembled to form a frame to utilize the cut piece as the door for the access opening is not known in the art and provides a very economical process for the manufacture of such wall panels.
In this invention the two sheet molding process is utilized to provide, a single molded panel from which cooperating parts are formed which, in combination, provide the wall unit and door with continuity in color and texture and will allow the inside to be of a different color and thickness from the outside.
The wall unit of the present invention provides its own rigidity to remove the need for supporting braces which were added to previously known polymeric wall panels formed by vacuum forming processes. Further, the shape of the outer and inner walls may be dedicated to their individual end use without compromising the shape of the other.